Passive Suicidal Ideation in Childhood.

Background: A growing body of empirical research shows that suicidal behaviors are prevalent in childhood. Yet, few studies have examined risk factors related to suicidal ideation (SI) among children aged 12 and younger. Aims: The current study addresses this gap. Method: A questionnaire was filled out by 1,350 Flemish primary caregivers (94.7% mothers) of 9-year-old children (50.4% boys, Mage = 9.45). Their responses were analyzed using logistic regression and independent samples t tests. Results: The presence of passive SI was reported in 10.5% of the children. A psychiatric, developmental, or behavioral condition (or multiple conditions), a learning disorder, impulsivity, aggression, and experiencing multiple stressful family life events were discovered as potential risk factors of passive SI in childhood. Limitations: The cross-sectional nature of this study meant that causality could not be inferred. In addition, it was based on reports of primary caregivers, rather than on reports from the children themselves. Conclusion: These new empirical findings can be used for the development of prevention programs and be taken into account in risk assessments of SI in clinical practice. Confirmation of our findings in a longitudinal child-reported study is needed.

Predictors and consequences of non-suicidal self-injury in relation to life, peer, and school factors.

INTRODUCTION: Numerous life, peer, and school-related factors have been found to be associated with non-suicidal self-injury (NSSI) among adolescents; however, most studies have not explored the possible reciprocal nature of these associations. The aim of the current study was to examine bidirectional and longitudinal associations between NSSI and several life, peer, and school-related factors (i.e., stressful life events, peer relationships, academic achievement, and attitudes towards school). METHOD: Community-based adolescents completed questionnaires assessing the variables of interest at three time points; age 12 (T1; 55.09% girls), age 13 (T2; 56.95% girls), and ages 14-15 (T3; 57.41% girls). In total, 529 adolescents provided complete data across all three-time points. RESULTS: Analyses showed a bidirectional association between NSSI and both attitudes towards school and stressful life events. Specifically, stressful life events at T2 predicted engagement in NSSI at T3, and NSSI at T2 predicted increased risk of stressful life events at T3. Similarly, having negative attitudes towards school predicted NSSI at T2, which, in turn, predicted negative attitudes towards school at T3. Further, academic achievement at T1 was negatively associated with NSSI at T2. Peer relationships were neither a predictor nor a consequence of NSSI. CONCLUSIONS: Our results suggest that NSSI can be both a predictor and a consequence of various life, and school factors. Focus on these factors in prevention and intervention efforts for NSSI among adolescents may be warranted.

Default mode network abnormalities during state switching in attention deficit hyperactivity disorder.

BACKGROUND: Individuals with attention deficit hyperactivity disorder (ADHD) display excess levels of default mode network (DMN) activity during goal-directed tasks, which are associated with attentional disturbances and performance decrements. One hypothesis is that this is due to attenuated down-regulation of this network during rest-to-task switching. A second related hypothesis is that it may be associated with right anterior insula (rAI) dysfunction - a region thought to control the actual state-switching process. METHOD: These hypotheses were tested in the current fMRI study in which 19 adults with ADHD and 21 typically developing controls undertook a novel state-to-state switching paradigm. Advance cues signalled upcoming switches between rest and task periods and switch-related anticipatory modulation of DMN and rAI was measured. To examine whether rest-to-task switching impairments may be a specific example of a more general state regulation deficit, activity upon task-to-rest cues was also analysed. RESULTS: Against our hypotheses, we found that the process of down-regulating the DMN when preparing to switch from rest to task was unimpaired in ADHD and that there was no switch-specific deficit in rAI modulation. However, individuals with ADHD showed difficulties up-regulating the DMN when switching from task to rest. CONCLUSIONS: Rest-to-task DMN attenuation seems to be intact in adults with ADHD and thus appears unrelated to excess DMN activity observed during tasks. Instead, individuals with ADHD exhibit attenuated up-regulation of the DMN, hence suggesting disturbed re-initiation of a rest state.

Towards a symbiotic brain-computer interface: exploring the application-decoder interaction.

OBJECTIVE: State of the art brain-computer interface (BCI) research focuses on improving individual components such as the application or the decoder that converts the user's brain activity to control signals. In this study, we investigate the interaction between these components in the P300 speller, a BCI for communication. We introduce a synergistic approach in which the stimulus presentation sequence is modified to enhance the machine learning decoding. In this way we aim for an improved overall BCI performance. APPROACH: First, a new stimulus presentation paradigm is introduced which provides us flexibility in tuning the sequence of visual stimuli presented to the user. Next, an experimental setup in which this paradigm is compared to other paradigms uncovers the underlying mechanism of the interdependence between the application and the performance of the decoder. MAIN RESULTS: Extensive analysis of the experimental results reveals the changing requirements of the decoder concerning the data recorded during the spelling session. When few data is recorded, the balance in the number of target and non-target stimuli shown to the user is more important than the signal-to-noise rate (SNR) of the recorded response signals. Only when more data has been collected, the SNR becomes the dominant factor. SIGNIFICANCE: For BCIs in general, knowing the dominant factor that affects the decoder performance and being able to respond to it is of utmost importance to improve system performance. For the P300 speller, the proposed tunable paradigm offers the possibility to tune the application to the decoder's needs at any time and, as such, fully exploit this application-decoder interaction.

Application of the name Lemna punctata G. Mey., the type of Landoltia Les & D. J. Crawford.

A recent (2011) attempt to change the previously designated type of the name of a duckweed species is discussed. Lemna punctata was first applied by Meyer in 1818 to a plant collected from South America, but original specimens have not been located. A prior neotype designation associated this name with a species native to parts of Asia, Australia and the Pacific, and widely introduced elsewhere, including South America. The species is generally treated by taxonomists in the genus Spirodela (either as S. punctata or the synonym S. oligorrhiza) or, more recently, as the sole member of the new (1999) genus Landoltia (as L. punctata). If accepted, this 2011 attempt to re-neotypify L. punctata would disrupt the names of two duckweed species as well as that of Landoltia. Nomenclatural arguments against accepting this new typification are provided, thereby supporting the continued usage of Landoltia in the sense intended by its original authors.

Methylphenidate, interstimulus interval, and reaction time performance of children with attention deficit/hyperactivity disorder: a pilot study.

Thirteen children with attention deficit/hyperactivity disorder (ADHD: DSM-IV-TR) participated in the pilot study. They carried out a Go/No-Go test with a short (2 seconds) and long (6 seconds) interstimulus interval (ISI) when on placebo and a therapeutic dose of methylphenidate (MPH). For the long-ISI placebo condition the responses were slow and inaccurate. This pattern of response may be due to underactivation of the readiness-to-respond state that is not fully controlled by effort allocation. Speed of response and accuracy were enhanced during the short-ISI placebo condition and the long-ISI MPH condition. However, the combined effect (short ISI and MPH) resulted in a fast but inaccurate response style. This pattern of response may be due to overactivation of the readiness-to-respond state. The data of the pilot study support the stimulus shift hypothesis: MPH administration result in deterioration on tests on which children had previously done well (short ISI plus placebo versus short ISI plus MPH). In addition, the data support the idea that ADHD is associated with poor state regulation rather than motivational (delay aversion) theories or temporal-processing/time-estimation theories of ADHD. The pilot study defined empirically an issue for further study with the larger controlled sample.

ERP correlates of error monitoring in adult ADHD.

The purpose of the current study was to evaluate whether error monitoring difficulties persist in adults with attention deficit hyperactivity disorder (ADHD) using the event-related potential (ERP) methodology. Adults with ADHD and age-matched healthy controls executed a visual Go/No-Go task with 25% No-Go trials. Performance and ERP correlates of error monitoring were compared between groups. At the performance level no difference was noted between groups. However, exploring the error-related potentials revealed that the error-related negativity (ERN) was the same for both groups, but that adults with ADHD showed a smaller error positivity (Pe). Based on these findings, we conclude that adults with ADHD are normal in early automatic error detection, but are deviant in later conscious evaluation of the error. The findings add to the increasing evidence supporting disturbances in error monitoring in ADHD and show that these problems may persist in adulthood ADHD.

HFA and ADHD: a direct comparison on state regulation and response inhibition.

This study examined whether children with high-functioning autism (HFA) are easily overaroused/activated and whether children with attention-deficit/hyperactivity disorder (ADHD) are easily underaroused/activated. This double dissociation was tested using a go/no-go paradigm with computer-paced fast and slow conditions and a self-paced condition. In the HFA group, a performance decline in the fast condition and slow performance in the self-paced condition were expected. In the ADHD group, a performance decline in the slow condition and fast performance in the self-paced condition were expected. No difference was found between groups for state regulation and response inhibition. Findings are discussed in the light of development, comorbidity, and subtypes.

ERP correlates of impaired error monitoring in children with ADHD.

OBJECTIVE: The purpose of the current study was to elaborate on error monitoring in children with Attention Deficit Hyperactivity Disorder (ADHD) using the ERP methodology. METHOD: Children with ADHD executed a visual Go/No-Go task with 25 percent No-Go trials; and a two stimulus reaction time task wherein a neutral warning signal (S1) was presented to inform the child to prepare for an imperative stimulus (S2). RESULTS: In both tasks, children with ADHD responded as fast as controls but made twice as many errors. In addition, they failed to adjust their speed of responding after making an error. Exploring the error-related potentials revealed that the error-related negativity (ERN) was the same for the two groups, but that children with ADHD showed a diminished error positivity (Pe). CONCLUSIONS: Based on these findings, we conclude that children with ADHD are normal in early error monitoring processes related to error detection, but show abnormal response strategy adjustments and are deviant in later error monitoring processes associated with the subjective/emotional, conscious evaluation of the error.

State regulation and response inhibition in children with ADHD and children with early- and continuously treated phenylketonuria: an event-related potential comparison.

BACKGROUND: The presentation rate of stimuli plays an important role in explaining the performance inefficiency in children with ADHD. In general, children with ADHD have been found to perform more poorly in conditions of relatively slow event rates as compared with fast and moderate event rates. The state regulation hypothesis states that these children have problems in correcting their energetic state necessary to counteract a performance decrement, which requires extra effort allocation. In this study, we investigated state regulation in children with ADHD and used children with early- and continuously treated phenylketonuria (PKU) as a clinical contrast group. METHOD: We measured the parietal P3 during a Go/No-Go task that incorporated a condition with a fast and a slow presentation rate. RESULTS: We were able to show that children with ADHD, relative to controls, responded more slowly and more variably in the slow condition only, which was accompanied by a smaller P3, suggesting less effort allocation. In contrast, the children with PKU did not show a state regulation deficit. The PKU group showed prolonged stimulus evaluation processing, as indexed by P3 latency, compared to controls and children with ADHD. In addition, they made more errors of commission than the controls and the ADHD group. CONCLUSIONS: Our electrophysiological data support the state regulation hypothesis of ADHD. Only the children with PKU had more problems in inhibiting pre-potent responding than controls, which is in accord with the prefrontal dysfunction hypothesis of PKU.

Quantitative analysis of sharp-force trauma: an application of scanning electron microscopy in forensic anthropology.

Scanning electron microscopy (SEM) has occasionally been used by anthropologists and forensic scientists to look at morphological characteristics that certain implements leave on bone. However, few studies have addressed techniques or protocols for assessing quantitative differences between tool marks on bone made by different bladed implements. In this study, the statistical variation in cut mark width was examined between control and test samples on bone using a scalpel blade, paring knife, and kitchen utility knife. Statistically significant differences (p < .0005) were found between cut marks made by the same knife under control and test conditions for all three knife types used in the study. When the control sample and test samples were examined individually for differences in mean variation between knife types, significant differences were also found (p < .0005). While significant differences in cut mark width were found, caution should be used in trying to classify individual cut marks as being inflicted by a particular implement, due to the overlap in cut mark width that exists between different knife types. When combined, both quantitative and qualitative analyses of cut marks should prove to be more useful in trying to identify a suspect weapon. Furthermore, the application of SEM can be particularly useful for assessing many of these features.

Effects of brain death and hemodynamic status on function and immunologic activation of the potential donor liver in the rat.

OBJECTIVE: To assess the effect on the function and immunologic status of potential donor livers of the duration of brain death combined with the presence and absence of hemodynamic instability in the donor. SUMMARY BACKGROUND DATA: Brain death, regarded as a given condition in organ transplantation, could have significant effects on the donor organ quality. METHODS: Brain death was induced in Wistar rats. Short or long periods of brain death in the presence or absence of hemodynamic instability were applied. Sham-operated rats served as controls. Organ function was studied by monitoring standard serum parameters. The inflammatory status of the liver was assessed by determining the immediate early gene products, the expression of cell adhesion molecules, and the influx of leukocytes in the liver. RESULTS: Progressive organ dysfunction was most pronounced in hemodynamically unstable brain-dead donors. Irrespective of hemodynamic status, a progressive inflammatory activation could be observed in brain-dead rats compared with controls. CONCLUSIONS: Brain death causes progressive liver dysfunction, which is made worse by the coexistence of hemodynamic instability. Further, brain death activates the inflammatory status of the potential donor liver, irrespective of the presence of hypotension. The changes observed may predispose the graft to additional damage from ischemia and reperfusion in the transplant procedure.

Retrospective searching for poisonous plant vouchers.

Few published reports of plant poisoning, whether experimental or accidental, document vouchers. This can be rectified by retrospective location of vouchers through determination of a collaborating botanist or herbarium of deposit. An absolute voucher is referenced in the toxicology report. For a probable voucher the report does not identify an herbarium specimen, but the report and the specimen label or sheet agree on plant name, collector's name, collection date and place. A possible voucher is perhaps from the exposure lot, but was collected by the collaborating botanist at a somewhat earlier or later date than the exposure date. On the other hand, a supporting specimen was collected by the collaborating botanist but is not from the exposure lot. Vouchers and supporting specimens for some species of Asclepias tested for toxicity by CD Marsh and coworkers were found in the US National Herbarium at the Smithsonian Institution, Washington DC.

Poisonous plant vouchers.

Every published report of plant poisoning, whether experimental or accidental, should document plant identification. The essential elements are: complete botanical Latin name including species, specific epithet and author(s); name of the collaborating botanist who identified the plant; and herbarium and collection number of a voucher specimen from the exposure lot. Additional information to aid identification might include plant photographs, drawings, and descriptions.

Cytogenetics of primary testicular nonseminoma, residual mature teratoma, and growing teratoma lesion in individual patients.

Residual mature teratoma (RMT) is often left behind when metastases of primary nonseminomatous germ cell tumors (NSs) are treated with chemotherapy. RMT is composed of fully differentiated somatic tissue. A growing teratoma (GTE) lesion may occur after (incomplete) resection of RMT. To shed light on tumor progression or the mechanism(s) of therapy related differentiation we investigated the chromosomal pattern of the primary NSs and RMTs in twelve patients, of the primary NS, RMT, and GTE lesion in one patient, and of the RMT and GTE lesion in two patients. Although several chromosomal differences are observed between the RMT and NSs and between the GTE and RMTs in the same patient, we obtained no evidence that specific chromosomal alteration(s) play a role in metastasis or differentiation.

Cytogenetic analysis of a case of myxoid liposarcoma with cartilaginous differentiation.

The cytogenetic analysis of a patient with a myxoid liposarcoma exhibiting cartilaginous differentiation is presented. A complex translocation involving chromosome 12, 16, and 19 was found, instead of the t(12;16), specific for myxoid liposarcoma. The involvement of 19q13 in a tumor with cartilaginous differentiation, and the assignment of TGF beta 1 to 19q13.1-13.2, which appears to play a role in the formation of bone and cartilage, suggest a possible relation between both.

No recurrent structural abnormalities apart from i(12p) in primary germ cell tumors of the adult testis.

Malignant transformation may be caused by gene deregulation resulting from specific chromosomal rearrangements, by amplification, by mutations in proto-oncogenes, by loss of tumor suppressor genes, or a combination of these. We investigated the role of numerical and structural chromosomal abnormalities in 102 cytogenetically abnormal cases of primary testicular germ cell tumors of adolescents and adults (TGCT) [32 seminomas (SE) and 70 nonseminomatous germ cell tumors (NS)]. We confirmed that an isochromosome for 12p, i(12p), is the only consistent structural chromosomal abnormality in TGCT, present in about 70% of our cases. Both the frequency and the number of copies of i(12p) are higher in NS than in SE. This may suggest that i(12p) is involved in tumor progression. Besides i(12p), several clonal structural chromosomal abnormalities were found, but none appeared to be specific. SE and NS had chromosome numbers in the triploid range, with significantly higher numbers in SE than in NS (average modal chromosome numbers of 73.4 in SE and 65.0 in NS). Both in SE and NS, some chromosomes were significantly underrepresented (e.g., 11, 13, 18, and Y) and others overrepresented (e.g., 7, 8, 12, 21, and X). In SE, a significantly higher copy number of chromosomes 7, 15, 19, and 22 was found and a significantly lower number of chromosome 17, compared with NS. These chromosomes may play an important role in the differentiation of TGCT.

Cytogenetics as a tool in the histologic subclassification of chondrosarcomas.

Chondrosarcomas are a heterogeneous group of bone neoplasms of which the basic neoplastic tissue is cartilaginous. Frequently the histologic diagnosis and grading of chondrosarcomas is difficult and the histologic appearance does not always reflect the biologic behavior of these tumors. Therefore, it is important to find other parameters that can be of help in the proper diagnosing and grading of these neoplasms. To this end, we attempted to correlate the chromosomal pattern of chondrosarcomas to their histologic subtypes and grades. The cytogenetic analysis of two intermediate-grade chondrosarcomas of bone, and a review of the literature, are presented.

Comparison of cytogenetic abnormalities and deoxyribonucleic acid ploidy of benign, borderline malignant, and different grades of malignant soft tissue tumors.

BACKGROUND: Both DNA flow cytometry and cytogenetic analysis have been used to study soft tissue tumors. With flow cytometry, the DNA content of a relatively large number of cells can be examined, but cytogenetic analysis gives more detailed information about genomic changes. EXPERIMENTAL DESIGN: In order to compare the advantages and drawbacks of DNA flow cytometry versus chromosomal analysis, 92 primary or recurrent malignant, 16 borderline malignant, and 13 benign soft tissue tumors were karyotyped after short-term culture. DNA ploidy was determined by flow cytometry of suspensions prepared from frozen or paraffin-embedded samples. From 97 patients, 121 samples were analyzed. RESULTS: On the basis of the results, four groups were distinguished: DNA-euploid tumors with normal diploid karyotypes (group a) or with abnormal (group b) karyotypes, and DNA-aneuploid tumors with normal (group c) or abnormal (group d) karyotypes. The findings in group b show that structural chromosomal abnormalities or minor numerical aberrations of chromosomes are not detected by DNA flow cytometry. In group c, the finding of tumors with an aneuploid DNA-profile and cells with normal karyotypes is most likely due to overgrowth of fibroblasts during culture and subsequent karyotyping of normal cells. CONCLUSIONS: The findings show that a) DNA flow cytometry has a higher success rate than karyotyping, b) both techniques are complementary, such that DNA flow cytometry gives an "overview", whereas karyotyping gives more detailed information; comparison of both techniques in individual cases leads to a better understanding of the chromosomal events that occurred during oncogenesis, c) histologically low grade tumors are generally DNA-diploid, but may have an abnormal karyotype, and d) histologically high-grade sarcomas tend to have an aneuploid DNA-profile; they are generally more difficult to karyotype.

Chromosomal aberrations in follicular thyroid carcinoma. Case report of a primary tumor and its metastasis.

We present the result of a cytogenetic study of a case of follicular carcinoma of the thyroid and its metastasis. Both tumors have a low number of chromosomes. The primary tumor is characterized by a idic(22;22)(p11;p11). The skeletal metastasis has also structural abnormalities of chromosome 22.